Collapsible container



Oct. 7, 1952 M. M. CUNNINGHAM COLLAPSIBLE CONTAINER 6 Sheets-Sheet 1 Filed Dec. 6, 1949 .A TIZ'ORNBY Oct. 7, 1952 M. M. CUNNINGHAM ,6 'COLLAPSIBLE CONTAINER I Filed Dec. 6, 1949 i e SheetsS heet 2 INVENTORZ v "55: 45) 7 BY i ATTORNEY Oct. 7, 1952 M. M. CUNNINGHAM COLLAPSIBLE CONTAINER 6 Sheets-Sheet 5 Filed Dec. 6. 1949 ATTORNEY Oct. 7, 1952 M. M. CUNNINGHAM COLLAPSIBLE CONTAINER 6 Sheets-Sheet 4 Filed Dec. 6, 1949 lllllllllll'l! aw ammm ATTORNEY M H m w 5 m. m e 2 M 0 2 m MIMI m mfg 2 m I M e I m m 6 4 z z 1 J MR 2 Am I Gm NW 1 MC E W% ML Mm m Oct.7,1 95 2 Filed Dec 6 1949 powdered dry materials.

Patented Oct. 7, 1952 COLLAPSIBLE CONTAINER Marion Cunningham, Woonsocket, R. L, as-

signor to United States Rubber Company, New York, N. Y., a corporation of New Jersey Application December 6, 1949, Serial No. 131,407

11 Claims.

This invention relates to agcollapsibla-fluidtight shipping container having the form of a barrel or drum and constructed primarily of coated cord fabric; that is fabricmade up of reinforcing cords embedded in rubber or similar plastic material. l The collapsible container contemplated by the present invention is preferably formed by the method disclosed and claimed in my copending application Serial No. 144.523, filed February 16, 1950.

Drum-shaped shipping containers formed of metal are used extensively, and the 55 gallon steel drum is used. in large quantities as a shipping, container for petroleum products, paint, dyes and other liquids andalso as a container for Such shipping containers ifmade ofaluminum or other non-ferrousmetal are expensive, andif made of steel,

as is usually the case, they tend to rust and therefore do notlast long unless they are frequently cleaned and repainted.

The present invention contemplates a flexible, tough, durable, shipping container having the shape of a barrelor drum and formed primarily of. reinforced rubber, to provide a liquid-tight container which will last much longer than the steel shipping drumsnow in extensive use, and which possesses other advantages.

The shipping container of the present invention preferably has a cylindrical body formed of cord fabric and rounded convexheads or ends also formed of cord fabric, similar to the cord fabric used in automobile tires. The cyclindrical bodyportion of the container isformed of two, four or more plies of cord fabric, each ply being positioned so that the cords extend helically about the drum and form a large acute angle with the longitudinal axis of the drum, with the cords of one ply crossing the cords of the'next ply at a pronounced angle. The heads of the container are likewise preferablyformed of two or more plies of cord; fabric, and arranged so that the cords of the different plies aredisposed at equal angles one to another, and the outer 2 a quired strength. The cylindrical walls of such drum-shaped containers are preferably stiff enough to. cause the container to stand alone when empty ready to receive the liquid or other material to be shipped therein, but such container is preferably flexible enough-to enable it tobe folded into a relatively compact condition so that these folded empty containers may be marginal portions of these headplies are posi- ,tionedto overlap the end plies of the cylinder portion of the container and are firmly bonded thereto.

Shipping containers constructed in accordance with the present invention mayvary in size from more of such plies, as needed to supply the restacked one on top of the other for shipment to the point of use.

Each shipping container constructed in accordance with the present invention preferably has a thick film of rubber at its inner face to provide a liquid-tight liner for the container,

and also has a thick film of rubber at its outer face to protect the underlying cord structure.

Such protecting films may be formed of ordinary rubber, or a synthetic rubber that is selectedfor its property of resisting the destructive action of the material to be shipped therein. For example a Buna N lining may be desirable in a receptacle to contain petroleum products, whereas for shipping many other materials a neoprene liner may be desired.

It is possible to make flexible containers possessing some ofthe featuresof the present invention by building the container over a collapsible or destructible form, then cure the container on such form, and finally collapse or destroy the form and remove it through an opening in the container. But it is'believed desirable inmany cases to build such containers on a rigid rotatably supported form. which can be used without collapsing, to support one container after another during the building operation, as herein after clearly disclosed. As soon as the container is made it is transferred from the non-collapsing form of a curing receptacle having the shape it is desired to impart to the finished container, and the container is cured therein while it is inflated into close contact with the wallsof the receptacle. Each container of the present invention has a hung hole or other filled opening. This bung hole need be only one to several inches in diameter for a large container design for shipping liquids, whereas if the container is designed to ship solid materials in the form of powder or small particles,,a much larger filling opening will be desired. The filling opening if relatively large should be at one end of the container and concentric with the axis thereof, whereas if a bung hole is used it may be located in one head of the drum off-set from such center, or in a side wall of the drum.

Metal shipping drums such as above mentioned collapsed it can be filled without the need of r venting the same.

The present flexible shipping container can be made extremely strong and durable, since it is preferably made of strong cord fabric, although it may be made of coated fabric such as coated duck. It will not rust or corrode and has waterproof inner and outer surfaces, and therefore should give years of useful service.

1 This container is liquid and air tight, and in many cases it may be desirable to provide the bung hole cap or other closure for the filling opening with an air valve, similarto that used in automobile tires, so that after the drum is filled with liquid or a powder materiaLgas or air under pressure may be forced into the drum to fully inflate the same or pressurize it, so that its cylinder walls willbecome stiff enough to prevent them from flattening appreciably under the weight of the container when resting upon its side. This will makeitjpossible to roll the filled and inflated container like a rigid drum. I

The present container is provided with a cylindricalbody and rounded convex heads or ends 'firmlyattached to the cylindrical body, and these convex heads preferably are provided with depressed or concave central areas, so that the container will be constructed throughout with curved surfaces that are well adapted to resistinternal pressures.

' In such flexible container it is important to prevent the depressed end areas from bulging outwardly under internal pressure and form protruding ends. This is accomplished by providing Within the container 2, flexible link connection between the heads to limit the distance therebetween and hold these heads cupped inwardly, so that the container will rest firmly on either end iii an upright position without rocking.

take the form of conically disposed tie cables attached'to each head and extending outwardly from a central cable or central point. This centrally disposed link or cable serves another function, in that it is proposed to provide each flexible container with a lifting loop or eye at one or both ends,'so that a hoisting hook can be engaged therewithwhen it is desired to lift the loaded container. The connecting'cable just "mentioned will serve to transmit a lifting pull from the eye at the upper end of the container direct to the head at the lower end of the container, so that the lifting load will be borne pri- "marily by the cable and'not by the side walls of If a lifting eye is provided at the container, each'end of the container, one maybe used to same. Ifthe layers of cord fabric forming the cylindrical body of the container are disposed at the -ccrrect opposite helical angles the body will not distort appreciably from its desired cylindrical shape when the container is subjected to an internal gaseous pressure or to the weight f a liquid In very large containers the flexible connecting link may j support the container upside down to empty the v confined therein or both. In the manufacture of high pressure rubber hose where the hose is subjected to lateral and longitudinal pressures, the practice is to wind the reinforcing cords ata heli cal angle .of about 52 degrees to the longitudinal axis of the hose, although the theoretical correct angle is about 56 degrees. I v I V In the construction of the container of the present invention the central link connecting one head to the other carries part of the longitudinal pull that would be exerted on the cylinder side walls if this link were omitted and the container inflated. On the other hand where the filled container is sitting on one end, or is suspended from the eye at the upper end, it is subjected to other forces than those present in an inflated hose. Therefore the helical angle used in the container of the present invention should be such as to resist the various forces just mentioned. The odd plies of cord fabric should extend in one direction in-the containerat the selected helical angle and the even plies should extend in the opposite direction at the same angle. If the cupped or concaved area at each end of the. container is rela tively large then the central cable will-take a large portion of the end pressure in an inflated container and the longitudinal pull on the cylindrical walls will be relatively small. On the other hand if this cupped area is small then the load upon the cable will likewise be small. 7

Since the cylindrical body of the container is made of cord fabric, in which each cord-is embedded in rubber with a substantial distance between the cords, it is possible to crowd the cords close-together" at each end of the cylindrical body as these ends are forced inwardlyto conform to the arcuate curved surface of the building form. As a result the marginal cylindrical cords, when forced inwardly a-short distance will move close together and form a smooth curved surface to which the marginal peripheral portions of the plies of the rounded heads can be firmly bonded. That is in constructing the shipping container of the present invention the end portions of the cylindrical plies forming the body of the container are criinped inwardly, but this c'rimped effect disappears as the cordsin this area are forced close together to form a smooth curved rim at each end of the cylinder, to which the roundedconvex heads can be firmly bonded.

It will be seen from the foregoing that the present invention contemplates a strong, durable, non-metallic shipping container formed primarily ofcord fabric and which isrlativ'ely rigid when inflated 'or pressurized. This convtainer is adapted to be used in place of the metal and wood shipping containers now in use, and due to its tough flexible construction and water and air imperviousouter and inner walls, it should give long shipping service, ;j-

The above and other features of the present invention-will be more fully understood from the following description when read in connection with the accompanying drawings; wherein:

Fig. 1 is a side elevation of a shipping container embodying the present invention, one sidewall being partly broken away to show the angle of the cords in an underlying ply; Fig.2 is avertical sectional view throughthe container of Fig. l; v

Fig. 3 is an end view of the bung-containing end of the container of Fig. l'; g Y Fig. 4 on a larger scale is a sectional view taken on the line 4 4 of Fig. 3;

of the container;

receptacle; Fig. 22 shows the container as partly removed "present invention.

""Fig. on a still larger scale is a sectional view of aportion of the construction shown in Fig. 4;

Fig. 6 is a top plan view of a clamping fi'iiture to be described; j l j '7 is asectional view taken on-the of Fig. 6;- l I "-fFig. 8" is a viewsimilar toFig. 1 but "shows the 'loadd container as suspended from a support- "ing hook, and also shows how the inner cable transmits the load from the upperto the lower "Fig. 9 shows the container of Fig. latter it has been emptied and" collapsed so thatit will occupy 'very'little space; d

Fig; 10' is a sectional perspective view of a piece of cord fabric such as may be used inconstructing 'thecylindrical-side walls andheads of the containerof the present"invention; 1

Fig. 11 is a side view era rotatablysupported, cylindrical building drum, having one body forming-ply of cord fabric shown thereon'in section;

Fig. 12 is a side view of a portion of the form oi 11 showinghow the marginal end portion oif-"the-bodyply is rolled inwardly against the "Fig; l4'is a. view similar to Fig. 13 and shows the marginalouter portion of the first end ply as bent-inwardlyinto overlapping relation with lindricalbodyand onehead of a four ply conhaving associated therewith a turning shell used *tcturn the cylindrical body inside out;

Fig.1? is a view similar to Fig. lfishowing the position of the turning shell and expanding 'amping chuck advanced to a partly turned position;

" Fig. 18"is a view similar to Fig. which shows one-half of the container as turned back over the other half readyto receive the secondhead Fig-19 is a view showing the four end plies of -a head'disposed in spaced relation to each other taken on line 20-40 of Fig. 16;

Fig. 21 is a view similar to Fig. 18 but shows both heads in place and part of the vulcanizing V in section;

Fig. 23 is'a sectional view throughthe closed 'vulcanizing receptacle, with the container of the present invention therein; and

Fig. 24 is a side view with parts in section of a modified type of the shipping container of the The particular embodiment of the invention illustrated in most of the views of the drawings Within the container is provided the central anchoring'strand or cable I5 attached to the cupshaped depressions I 3 and 14 to limit the distance between these cuppedends when the container is filled or pressurized, and the length of thiscable present invention is to be producedfinflarge quantities. the time and cost of buildingsuch should be such as normally to hold both heads cupped-inwardly-asshown in Fig; 21 1 The head .I l is shown as provided witha bung hole formed by the meal sleeve [B having the closure or cap 11. This head H is alsoprovided with a loop-oreye l8 by means of whichthe shipping container may beliftedg-as shownin Fig. 8. The eye is secured to'the cable liby a construction which will be hereinafter described. The shippingcontainer so far described can be made by building the same over a rigid form, the outer. surface of which has'the general c-ontour'it is desiredto impart to the interior of the-finished container; Such form; for example, may be made of plaster,-or stiff paper impregnated with glue, and canbe broken upor reduced to a soft paper pulp so that the' form cafnbe -re moved through the bung hole, 'aftertherein forced rubber container is vulcanized. When however, such a destructibleiorm is used itis necessary-"to go tothe expense of providing a new form for each-container; It is possibleto 'avoidthis expense, in building a containerhaving'a relatively large'opening at one-end,"*by usingla collapsible or folding form made ofrigi'd material such as folding metal parts. This would make it possible to build acontainer such as can templated bythe present invention upon a collaps-ible cylinder'form, insert the assembly =0f form and container in a pressure chamber, and

vulcanize thefinished container on such form.

Then collapse the form and remove it throughan end opening in one end of the container.

-While the't'wo methods just mentione'dniay be employed in constructing containers embodying a numberof features of the present inven tion, it is deemed preferable in many cases to employ the' method and apparatus hereinafter described in building such collapsible containers.

' If the shipping container contemplated by; the

containers can be reduced by forming them upon a permanent and non-collapsible metal form,

such as shown and hereinafter described. That isthe container is produced on the form shown in Fig. 11 'ot the drawing to the extent of forming the cylindrical body portion and one rounded head, of the desired number of coated fabric plies. 7 Then the cylinder body portion ofsuch container is turned inside out to the extent shown in Fig. 18 to position one end of the body all! adjacent the other, so that the second head can be applied, whereupon theturning of, the container is completed to remove the container from the building, formand at the same time place it inside or a curing or vulcanizlng mold .tobe described; i

In Iconstructing the collapsible container of the present invention it is desired to use a cord fabric such as shown in Fig. 10, but a coated fabric such as awoven fabric coated with rubber may be used. at least in some portions of the container. The cord fabric 19 shown in Fig. 10 is formed of the cords 20 embedded in rubber or other plastic material, and it will benoted that the cord .fabric of Fig. 10 has a thicker coating ofrubber on the lower face than on the upper face. Such a construction is desirable for the innermost ply and outermost-ply so as toprovide a thick film of rubber over the cords at the inner face of the container to prevent the confined liquid from penetrating through such rubber film tothe cords, and it is desirable vtainer is being built.

in the outermost ply of the container to provide a thick protecting film of rubber over the outer layer of cords. The intermediate plies of cord fabric preferably should have the same thickness of rubber at each face of the cord fabric The coating material used to embed the cords may be naturalrubber, synthetic rubber or a flexible rubber-like material as above stated. The cords 20 may be formed of cotton, rayon or other textile fibers or filaments, and these cords preferably are spaced a substantial distance apart, that is such space may be approximately equal to the diameter of the cord, so that when the cord fabric is bent around the curved end of the building form, as hereinafter described, the cords will have sufilcient room to move close together and conform accurately to this arcuate curve of such form.

- The detailed steps which are preferably employed in constructing the collapsible shipping container of the present invention will now be described, .as such container is built upon a permanent non-collapsing form, such as the cylindrical form 2| shown in Fig. 11 and other views of the drawings. This form is supported and rotated by the driving shaft 22, and the outer end of this form may have the relative flat face 23, and it is important to provide the form with a relatively large radius 24 extendin from the cylinder portion of the form 2| to the end 23. The building form is provided at the center of its end 23 with the positioning pin 25 which serves to center the end plies as the con- At the other end of the cylindrical form 2| is provided an expansion chuck having the arcuate expansion jaws 26 which are supported by a head, not shown, so thatthey can be forced radially outwardly from the collapsed position in which they are shown in Figs. 11 and 15 to the expanded position in which they are shown in Figs. 16' and 17. Each jaw2'6 has an outwardly extending rib 21 which acts as a guide for the cord fabric plies as they are placed upon the cylindrical form, and each jaw. 26 also has a curved, work-engaging blade 28. In order to bridge the gap between these jaws when the chuck is expanded it is desirable to provide a thin plate 29 crossing such gap and'which is secured to one jaw by a rivet 3B and projects into a groove in the next jaw as shown in Fig. 20. The expansion chuck formed of the jaws 26 normally is supported atone end of the form 2|, as shown in Fig. 11, and independently of such form so that it will not rotate therewith, but is adapted to be expanded by cams or other means not shown, and also is adapted to be moved lengthwise of the form.2| to aposition in which it is shown in Fig.1? and also cords will form an angle of somewhere near 50 to the longitudinal axis of the finished container. .These cord fabric plies are laid upon the form 2| so that one edge will engage the rib 2T'and the cords of the odd plies willextend across the longitudinal axis of the drumin one; direction,

an le.

tion the opposite end of such ply relative to the end wall 23 of the form 2| as shown, and this ply should be positioned upon the form to entirely surround the form with its opposite ends meeting or overlapping very slightly. As soon as the first ply |9 is placed about the form 2| with one end projecting slightly beyond the end wall 23, then this protrudingend of the sheet I9 is bent or rolled inwardly to conform accurately to the curved portion 211 of the form as shown in Fig. 12. And since the cords 20 of the fabric H! are spaced a substantial distance apart they will move inwardly towards each other as this fabric is rolled about the arcuate end of the form. As a result the cord fabric will lay more smoothly about such rounded end than would a closely woven reinforcing fabric such as duck. This operation ofworking the protruding end of the ply l9 intosmooth contact with the arcuate portion 24 of the form may be easily performed by rotating the form 2| and using a stitching wheel or roller 3| (see Fig. 12) which is rotatably supported by a bracket 32 that is pivotally mounted at 33 on a supporting structure, not shown, but located below the cylindrical form 2|. The roller 3| may be rocked about its pivot 33 by a handle 34, and may also be tilted slightly by rocking this handle to thereby facilitate the travel of this roller about the are 24 towards and from the central axis of the rotating form through the arc :c-sc of Fig. 12.

After the protruding end of the first ply H! has been bent inwardly into contact with the arcuate surface 24, then an end ply such as indicated by 35 in Fig. 19 may be applied. This end ply may be formed ofcord fabric similar to that used for the body portion of the container, and three of the four end plies shown are designated by 35, 35a and 35b and resemble a rectangle with rounded ends. This shape is due to the fact that a few cords have been omitted from two sides for a purpose, to be described. The fourth end ply, which will contact the liquid at the inner face of the container when the same is in use, is formed of cord fabric in the form of a complete circleas indicated by36 and tothis disc 36 is secured a disc of rubberv31 which is slightly larger in diameter than the disc 36.. The purpose in providing this larger disc of rubber 31 is to cover the cords completely at the inner face of the container so as to prevent the liquid contents of the container fromreaching the cordsand causing objectionable wicking.

Each of the end plies shown in Fig. 19 preferably is provided with a central hole adapted to fit overthe pin- 25 as shown in Fig. 13, as this provides a simple means for centering each end ply relatively to the form 2|. As soon as the ply 35 is placed in the position in'which it is shown in "Fig. 13 it is stitched or rolled into overlapping engagement with the end portion of the ply l9 into bonding engagement therewith as shown in Fig. 14, the rolling wheel 3| being employed and the form rotated at this time.

9 After the,: first-body; ply l9 and first end ply 35am securedin place asshown in Fig. 14, the other body plies-and end plies are similarly applied one at a time to build up a container having. the desired wall thickness, four such plies being shown in Fig. 15 in the cylinder body por- Ltionof thecontainer and also in the end portions thereof; One of the plies 35a or 351) preferably has adhered thereto the metal rings 3 38 so: as to embedsuchrings in'the head of the container wherelthey later will serve to help anchor in placethe metal fixtures to be described. The reasona few. cords are omitted from each side of the discs. 35, 35a and 35bas shown in Fig. 19 is to reduce the bulge they form at .39 and allow this portion of the container to conformto the I shape of the vulcanizing receptacle.

. Since as hereinvcontemplated the container is built upon the form 2! inside out and later turned the. ply l9 which contacts the form 2| will, become the outermost ply in; a finished molded container, and the outermost plyshown in Fig. 15 will become the lining ply in the finished vulcanized container... After the several body'forming plies and end plies have been as- I sembled and their overlapping edges bonded one ;to the otherfas indicated by 39 in Fig. 5 and other in spaced; relation thereto, and it will be noted that. the expansion chuck formedof the sections 26 hasbeen expanded to enlarge the inner end ofthe. container and force this'end into airtight co ntact witht the inner periphery of the .casin'g14flfso that it is now possible to build up airlpressurewithin the casing 40 without air escaping adjacent the expanded end of the cylinder .IDlw If air; is now forced into the casing 40 through anair supply pipe 4| to build up pressure therein,. .this pressure will serve to move the casingin .aleft-hand direction viewing Fig. 16 to therebyinitiate turning of the container. As

this .turning operation proceeds as shown in Figs.

.I'IhandlSQthe air pressure just mentioned will Serve (1') to cause the mainportion of the cord fabric .co'ntainerlto hugthe form 2! tightly so as not to slip endwise thereuponand (2) to maintain a film of airbetween the non-moving and moving portions of the container during the turningjoperation, to thereby prevent one tacky .surface from being dragged over another. In

this way the cylinder wall of the container is readily. turned. This turning operation should be. continued until the turned portion reaches the position. shown "in Fig. 18, to position this end so that it will. overlap the end plies of the second head, just the desired amount. Said second head isthen built up by stitching these end pliesone at a time, starting with the ply 36, to the proper inward turned portion of. the cylindricalbody to form. the double ended container shown in Fig. 21. The overlapping plies are stitched one to the other by employing. the roller 3|. Since thesecond head II is formed over the first head [2 as shown in Fig. 21 one head between the two heads II- and l2.

1 other.

will be slightly larger than the other at this time, but since .the entire container is expanded by internal pressure to fit the inside' of the vulcanizing receptacle, this is not important. The cord fabric usedin making .the body ltlfpermits such body to expandyoutwardly as it is turned. .After both heads H andl2. aresecuredtotthe cylindrical body' portion of the receptacle as shown in Fig. 21,.the container is further peeled or turned to remove it from the form 2 l, and at the same time deposit this tacky uncuredfcontainer within a curing mold or vulcanizing mold, which mold as shown in Figs. 21 to 23 comprises a central cylindrical portion 1'42 and the hinged end-portions 43 and 44 havingthe hinges 45. This vulcanizing receptacle ispar'tly shown in Fig. 21 as having the end 43 wide open and the cylindrical portion 42 in position to .beadvanced overv the cord fabric container far enough to bring. the head 44 of this vulcanizer into contact with the outerhead ll of the container..

I Since} as above stated the flexible container contemplated by the present invention is formed with cupped shaped depressions l3 and i4 at the ends thereof, the. end walls ordoors 43 and 44 of the vulcanizer are preferably shapedas shown to the contour it is desired to impartto the outer wall of the finished vulcanized heads II and/l2 of thecontainer. Likewise the cylindrical portion 42 of this vulcanizer is preferably given the finish it isv desired to impart to the outer cylindrical body of such container. After the vulcanizer hasbeen placed over the. partly turned container shown in Fig. 21,.further turning of the container effected by introducing air underpressure between the inner faces of the heads I I and I2. This is done by providing an air pressur pipe 46 attached to the central portion of the vulcanizer head 44 and; the inner end of this pipe will push the centering pin 25 inwardly into its receivingbox 41 against the resistance of the coil spring 48, and force air into the space Separation of these heads may be assisted by providing the vulcanizer head 44 with the central vacuum cup 50. The arrangement is such that a suctionaction isexerted upon the head H by the vacuum means just described and at the same time air is forced into the space between the heads H and 12. by the compressed air pipe 46. Air pressure is built up by the means just described between heads H and I2 to force these heads apart, and this will move the vulcanizer to. the leftasthe container is further turned, as willbe apparent from Fig. 22, and as the air pressure is built up within theturningcontainer it'willmaintain a thin film of air between the moving and non-moving portion of the cylindrical wall to prevent one from adhering to the This internal air pressure will serve. also to force the unvulcanized container into contact with the various walls of the vulcanizer. .As the container is gradually filled with air and the operation of turning the same within the: vulcanizer advances the vulcanizer will move away from the form 2| so that the door 43 may be closed, and as this is done a tapered hollow plug 5! will enter the hole in the head I2 to plug this hole and at the same time connect the interior of the container with a gauge 52 that indicates the pressure established within the container to hold its walls in snug engagement with the inner walls of the vulcanizing receptacle. The end wall 43 of the vulcanizer is preferably provided with a vacuum cup 49and vacuum pipe 50 similar to the vacuum means above described and ing the fluid receiving spaces 53 adapted to be supplied with'a heating fluid such as hot oil or steam.

After the cord fabriccontainer has been suificientlyvulcanized within the receptacle 42, 43, 44, a doormaybeopened and the container removed ther'efroin. This completes the operation of manufacturing" he container contemplated by thapresent invention, except for installing the metal fixtures that are best shown in Figs. 4, 5, '6 and '7.

The centrally disposed tie cable l above described has each end thereof, in the construction shown, firmly anchored to a disc 54 having a threaded integral post 55, which post is adapted to receive a threaded cap or nut 56. The arrangement is such that the discs 54 attached to the opposite ends of the cable l5 may b inserted through a hung hole cut in the container, whereupon a post 55 is inserted in a central hole provided in each head. The nut 56 having the wrench holes 5! is engaged with the threaded post 54 and screwed down tdclamp the parts firmly in place asshown in Fig. 4, with the outer marginal edges of the clamping members 54 and '55 cooperating with the strengthening ring 38 to provide a strong, fluidtight, anchoring means for the cabl at each end of the container. The lifting eye; or loop I8 is firmly secured to the post 55. When desired the container may be lifted by a hoisting chain 58.

The container of the present invention is also preferably provided with a filling and emptying hole, which in the construction shown takes the former a hung hole that may be formed in a side wall of the cylindrical body, or at the highest point in the container if desired to facilitate draining of all of the liquid out of the container. 'Such bung hol is shown as provided at one end of the container near the central anchoring means, where it is protected to some extent by the highest point of the head. The bung hole is formed, as above stated, by the sleeve I6 having the closure cap IT. This sleevelfi has secured thereupon the clamping sleeve 59 and lying between flanges upon these sleeves is a reinforcing ring 38. The cap I! may have an air valve Bil similar to that used in pneumatic tires so that after the container has been filled with a liquid or powdered material air or gas may be introduced to pressurize the container. Such air or gas pressure may vary from about 1 to pounds per square inch as desired, and it will serve to keep the walls of the container fully inflated so that the containermay roll on its side like a rigid drum. Furthermore the gas used to inflate the container may, if desired, be an inert gas such as nitrogen used to preserve flour or other fine materials shipped in the container.

It is possible as above mentioned to manufacture the collapsible container contemplated by the present invention in various sizes. The con 12 tainer disclosed in Figs. 1 to 23 of the drawings is a type well adapted for use in shipping liquids therein such as petroleum products, paints', dy es and the like and having a capacity of less than gallons. In building very large containers having a capacity anywhere'from several hundred to several thousand gallons it may be desirable to change the construction shown in Figs. 1 to 23 inclusive to that of the modified construction of Fig. 24, wherein the sidewalls 5| of the container may beformed the same as the sidewalls IU of the container above described, except that a greater number of cord fabric plies will be used in the large container: of Fig. 24. This container of Fig. 24 has the upper'end 62 and lower end 63 which are preferably formed of end plies similar to those shown in Fig. 19, except that more than four end plies for .each

end will probably be required. Because of the.

large size and weight of this container of Fig. 24 it is desirable to use a relatively large metal reinforcing head at each end of the container which will now be described. I

Since the same type of metal reinforcing head may be used at both ends of the flexible container, the description of one head will suflice for both. The upper metal reinforcing head 64 and lower metal reinforcing head 65 may be formed. of aluminum, or of steel if a stronger metal is desired, and each head has the form of a curved disk 66 which is surrounded at its periphery by a laterally extending hoop-like flange 68', and rigidly secured to the disk portion 66v and flange portion 66' are a number of curved bracing bars 6'! which may readily be engaged by the lifting hooks of a hoist employed to lift the container.

This large container of Fig. 24, like the smaller container shown in the other figures is provided with a centrally disposed internal cable system forming a connection between the ends and adapted to limit the distance ther-ebetween, but in view of the great weight of this large container when loaded, it is desirable to employ a number of branch cables such for example'as the six upper cables 68 and six lower cables 68, each of which has one end firmly anchored to a metal connection 69. The upper metal connection 69 and lower metal connection 69 are connected by a heavy anchoring cable H1. Each cable 68 has secured to its outer end a'specially constructed metal head H having a rounded flat face adapted to abut against an inner face of the multi-ply cord fabric container end 62 Or 63 and to be clamped thereagainst by bolts 12 that extend through holes in the metal disk 66 and in the cord fabric pliesand into threaded engagement with the heads I l, as shown in the drawing. The arrangement is such that the cord fabric plies forming the end 62 or 63Jare firmly clamped between the inner face of the metal disk 66 and the cable anchoring heads H.

The metal reinforcing head 64 and fabric end 62 are shown as having a relatively large central opening in which is fitted a metal ring comprising the cylindrical wall !3 that is internally threaded and this ring has the outwardly extending annular flange 14. This flange has the projecting bosses 15 that are internally threaded to receive the clamping bolts 16 that clamp the flange T4 to the disk 66 with the end fabric 52 therebetween. The threaded ring 13 has secured therein the threaded closure TI having the threaded central plug 18. The container ends 62 and E33 are preferably provided with the reinforclngmetal rings 19 that cooperate with the clamping memberslifi and 'ldfand also with the reinforcing rings that cooperate with the cable anchoring heads H, similar to the reinforcing rings 38 above described; "The cord fabric side Wallsfil and thecordfabric end plies 62 and B3 areoverlapping and firmly securedtogether at 8|, similar to th -overlapped seam 39, see Fig. 5. ff 1 By. providing the large metalheads and 65 ofFig. 24 having the branchcables 6 8 and main cable "forming a connectionfltherebetween a very strongconstruction is provided, which makes it possible to rest the container on either'end, or lift the loaded container from either end by means of a power hoist without injuring the container or distorting it unduly, and thisfconstruction makes it possible to roll th container on itssi'de like a drum, particularly if the container is pressurized tomaintain all walls thereof fully "inflated. A large container of this type' is well adapted foruse in shipping and storing flour, meal, grain and 'othed dry materials and if after the container isfllled with such'material an inert gas such as nitrogen or carbon monoxide is introduced therein, insects or bacteria. upon such material will be destroyed and the'grain or other material can be kept in good condition;

\ An important feature of the .present container residesfin thegshapeof the end portions ofthe container whereby it is well adapted to resist internal pressures. ,This is'accomplished, as above pointed out, by f-or min'g the body of the container with cylindrical walls and the heads of ,the container, in the construction of Figs. 1 to 23, with convex walls having depressed or cupped center portions, and by also providing a connecting linkfbet'ween such heads or centers to keep them from bulging outwardly. In order to prevent the 'convexed end walls from being subjected to excessive strains, whenfthe container is loaded orfipressurized, the. container should have a relatively large curve where the end walls .and side wallsfmeet andjoverlap, and such curved end, portions of thecontainer should form a zero angle with the cylinder body walls at the approximate position of y of Fig. 4 of the drawing. The location of the hump or high point z is less important asthis hump may lie either closer to or further from the central axis than shown in Fig. 401' the drawing. If this hump z is located far from the central axis of the container then when the container'isinflated a large portion of the pressure upon the heads H and I2 will be exerted upon the connecting cable l5.

Onthe other hand if this hump is positioned near the central axis, thentheforce upon the cable J -wi1 l be reduced while the longitudinalpull upon the cylindrical walls will beincreased.

, If the cable I5 should be omitted, then the central portion of the heads ii and I2 would extend outwardly when the container is pressurized. 1 i This would pull 'theyside walls, at the lendsof the cylinderinwardly and set'up undesired bending forces; In the? absence of the cable IS the side walls would be subjected to the transverse and longitudinal pressure of the confined fluid, and to prevent the cylindrical walls from bulging outwardly out of shape under such forces, the reinforcing cords 20 should lie at an angle of about 52 to thelongitudinal axis of the vulcanized container. When however the cable '15 is employed the longitudinal p-ull ,upon the cylinder walls will be reduced, with the result that an angle slightly greater than 52 may be employed, depending somewhat on the location of the hump 2 which controls the size of thedepressed cup portion of the heads. However the shipping container of the present invention when filled with liquid or other material, willbe subjected to added internal forces due to the weight of the material therein, and these forceswill change when the container rests onone end or on a side, or is suspended as shown in Fig. 8. All these conditions will need to be considered in selecting the cord angle, which should, "itis believed, be slightly above 52 degrees to avoid substantial deformation of the container. e

The ratio of the length of the-container to its diameter may vary in a fairly wide range and still meet the requirement of good design. The four ply container shown in the drawing is well adapted for use as a 55 gallon shippingjc'ontainer for petroleum products, acids, alk'alis, paint,dyes and other liquids. When such a container is empty it can be collapsed into a small space as shown in Fig. 9 for stacking one on top 'of'th'e other and shipping to the return point. Furthermore, while the container is preferably stiff enough to stand upright when empty, so that it is easy to fill, its ability to collapse under slight pressure, makes it possible to collapse'the containeras it is being emptied so "thatffthe contents may be removed from the 3 container without the need of venting air therein, and also the collapsed container can be filled without the need of venting air therefrom.

In addition to the advantages 'above "mentioned, the present container will not rust [or corrode, particularly if the metal parts above de scribed are made of stainless steel and the st'rong durable cordfabric should be capable "of resisting many severe blows and of giVingyearS of shipping service. 1 j

fHaving thus described my invention, what I claim and desire to protect by Letters Patent i's: j 1, 'A collapsible fluid-tight shipping container formed primarily of coated cord fabric andhavinga cylindrical body and rounded convex heads.

js-aidbody being formed of pli-es' -of coate'd' c'ord fabricarranged so that the cords of one ply form a substantialanglewith the cords of the next 'plyan d the end portions of thecylindrical body form a substantial angle with the cord's' o'f the "next plyand the end portions of the cylindrical body being bent inwardly a short distance entirely around the body, each rounded convex head being formed of a pluralityof pliesof reinforced fabric having the marginal edge portions lapped over said end portions and firmly bonded thereto, and one of said heads having a hung hole and closure therefor and an air inflating valve in this closure.

3. A liquid-tight shipping container formed primarily of cord fabric and having a discharge opening and closure therefor, said container comprising a cylindrical body and rounded heads, the body being formed of a plurality of plies of cords embedded in rubber so that the cords can shift considerably in the rubber before it is vulcanized and each ply having its cords disposed at a large acute angle to the cylinder axis and in crossing relation to the cords of the next ply, the plies atthe ends of the body being bent inwardly to form curved flanges entirely around the body, and-said hea-ds being formed of fabric plies that overlap and are bonded by vulcanized rubber to said curved flanges. v

4. A liquid-tight shipping container formed primarily. of cord fabric and having a discharge opening andclosure therefor, said container comprising'a cylindrical body androunded heads, the bodybeing formed of a plurality'of plies of cords embedded in rubber so that the cords can shift considerably in the rubber before it is vulcanized and each ply having its cords disposed atalarge acute angle to the cylinder axis and in crossing relation to the cords of the next ply, the plies atthe ends of the body being bent inwardly to form curved flanges in which the cords of each ply are crowdedclose together in the flanges, and said headsbeing formed of plies of cord fabric that overlap and are firmly bonded by vulcanized rubber to said flanges.

5.. As a new article of manufacture a nonmetallic shipping drum having a cylindrical body and rounded convex heads, said body being formed of plies of coated cord fabric arranged so that the cords of one ply form a substantial angle to the cords of the next ply and such cords lieiat an angle of about 52 to the cylinder axis, the ends of the cylinder being bent inwardly on an arc and said heads being formed of plies of coated fabric having marginal edge portions which overlap and are bonded by the coating material to the'bent-in portions of said body.

6.-A collapsible shipping container formed of coated cordfabric having a cylindrical body and convex-concave heads, said body being formed of plies of coated cord fabric arranged so that the cords of one ply form a substantial angle with the cords of the next ply and the end portions of the cylindrical body being bent inwardly a short distance, each rounded head being formed of a pluralityof plies of coated fabric having marginal edge portions overlapping and bonded tothe bent-in portions of the body, and each head having a central concave cupped portion and acentral tie connection within the container between the cupped portions.

-marginal edge portions overlapping and bonded fto the bent-in portions of the body, and the container being flexible enough to be collapsed when empty to a small fraction of its full size.

. .8. A collapsible closed shipping container, of

many gallons capacity for transporting materials,

comprising a cylindrical body portion formed of plies of coated fabric bonded together, and rounded convex heads also formed of plies of coated fabric bonded together andarranged with the outer marginal portions of the head plies overlapped andbonded to the outer ,end portions of the body plies, and said container having a discharge opening that is ,not more than three inches in diameter and which is the largest opening in the container, and a tight closurefor such discharge opening. V

9. A closed shipping container having. a filling opening and formed throughout of curved surfaces, comprising a cylindrical body portion formed of coated fabric and rounded convex heads also formed of coated fabric and having their outer marginal portions secured to the outer ends of the cylindrical body, a central, tie link within the container and. connecting said heads to hold the central areav of each cupped inwardly, whereby the container is formed throughout of curved walls'that are well adapted to resist internal pressure when inflated.

10. A collapsible shipping container having a cylindrical body and rounded convex heads, said body being formed of plies of coated cord fabric arranged so that the cords of one ply form a substantial angle with the cords of the next ply and the end portions of the cylinder bodybeing bent inwardly with a very gradual curve near the cylinder walls,- each head being formed of plies of coated fabric having their marginal edge portions lapped over said bent in end portions and bonded thereto, and a tie link within the container and connected to said heads to hold the center portion of each cupped inwardly.

11. A closed shipping container formed with curved side and end walls, comprising'a cylindrical body portion formed of coated fabric and rounded convex heads also formed of coated fabric and having their outer marginal portions overlapped and secured to the end portions of the cylindrical body, each head having a cupped sunken center, and a central tie. link connected to the centers to limit the distance therebetween, whereby the containeris formed with curved side and end walls thatare welladapted to resist internal pressures.

' MARION M. CUNNINGHAM.

. REFERENCES CITED The following references are of record inthe file of this patent:

UNITED STATES PATENTS Great Britain Aug. 6, 1941 

